George murray



Die for Cutting the ea d on Pipes. No.239.,531. Patented March 29,1881. 7

INVENTOR ATTORNEY MPETERS. HOTO-UTHDGRAPHER, WASHINGTON, nv C.

UNITED STATES PATENT QEFICE.

GEORGE MURRAY, JR, 0F OAMBRIDGEPORT, MASSACHUSETTS.

DIE-FOR CUTTING THETHREAD ON PIPES.

SPECIFICATION forming part of Letters Patent'No. 239,531, dated March 29, 1881. Application filed September 15, 1880. (Modem To all whom it may concern Be it known that I, GEORGE MURRAY, Jr., of Gambridgeport, in the couuty of Middlesex and State of Massachusetts, have invented a new and valuable Improvement in Dies for Outting the Thread on Pipes; and I do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being-had to the annexed drawings, making a part of this specification, and to the letters and figures of reference marked thereon.

Figure 1 of the drawings is a representatioii ofa back view of the die. Fig. 2 is a front view of the same. Fig. 3 is a section through the line mm. Fig. 4 is a cross-section through the line y y.

. This invention has relation to dies for cutting screw-threads on pipes; and it consists in the construction and novel arrangement of the bracing-bead in frontof each section, the end of said head forming a cutter for the initial portion of the work and the formation of the bead in the concave portions between the sections, rendering these concavities somewhat flaring or enlarged in their outer or rear portions, so that the chips and oil will be readily worked out, all as hereinafter shown and described.

In the accompanying drawings, the letterA designates the face, and B the rear surface, of the die. G indicates its aperture, having the raised sections a serrated to form the cutters, as shown. Between each two of the cuttersections a is formed a concavity, b, which is made with a curved wall, which is somewhat flaring toward its rear opening or outlet portion, 0. The inner portion of the concavity where it enters on the work is of less diameter, a bead, d, being raised inside the concavity, and extending from each cutter-section to the one immediately following. This bead forms a strong brace for the sections, and is serrated at its end to form the initial cutters e, which set a little forward, but are not so much raised as the main finishing-cutters 7c of the sections.

The head this inform convex on its inner surface, so that the line of initial cutters e is also somewhat convex or winding. The finishingcutters kextend in straightlines from the initial cutters, the line of each series being perpendicular to the rear surface of the die, or nearly so, as shown in the drawings. This form of dieis easily cut and is very effectual in its operation. The projecting line of initial cutters formed on the head end facilitates the feed materially, grasping the work when in action,and feeding the die gradually but effectively thereon. The cutting-edges of the teeth 0 k are at right angles, or nearly so, with the back of the die, and theywork very rapidly, and are sufficiently strong because of the bracing-bead in the entrance portion of the die, which strengthens theinitial cutters, which prepare the way for the others.

An important result found in the use of this die is the ready discharge of the chips and oil, which work out of the larger ends of the concavities between the sections.

I am aware that a die having the initial or starting end enlarged is not broadly new, and I aim to claim only the construction herein shown and described. I

Having described this invention, what I claim, and desire to secure by Letters Patent,

GEORGE MURRAY, JR. [L. s. j

Witnesses:

W. H. HALL, JOHN M. MURRAY.

A die for cutting thread on pipes, having in i it i 

